We revisit the interview here to reveal a candid portrait of an

ordinarily private powerhouse.

It's early July in New York. The heat is so intense it is hardly possible to take a breath without feeling like you've inhaled at the open door of an oven. As Rupert Murdoch arrives in London to face his own grilling, so (to my amazement, given she has pulled out of almost all her other press commitments) his wife Wendi Deng arrives at the Hudson Hotel, fresh off her plane from Los Angeles.

Dressed simply in a pair of black jeans, a T-shirt emblazoned with the name of her film, Snow Flower and the Secret Fan, a hoodie and a pair of flat pumps, the only clue to what is happening in her private life are the dark circles under her eyes. There is no fuss; no army of PR toughies, just Wendi and her assistant, Crystal.

Full of apologies for having kept us waiting, Wendi then has to take a 15-minute call on the terrace of the suite from which we are working. Watching her standing out there with her arms wrapped around her frame, clutching a phone to her ear, I wonder if it is her beleaguered husband she is talking to. The call complete, she returns, smiling, and settles into hair and make-up for our shoot.

Although Deng must be going through a time of extraordinary stress, she does a very good job of keeping things light, chattering away about what a good time she has just had in Sun Valley at the Allen & Co annual conference where world leaders, philanthropists, and business leaders meet; the Murdochs are regular guests. Wendi loved listening to Oprah Winfrey talk, and hanging out with her stepson Lachlan, his wife Sarah and their kids. "Such fun!" she says in a loud, rat-a-tat staccato. She has a strong Chinese accent, and speaks quickly in broken sentences that are initially hard to follow.

I have been asked by Wendi's assistants not to bring up what is happening in London (a phone-hacking scandal of such magnitude it has tainted the very top echelons of parliament, the police and the newspaper industry, led to multiple resignations, and seen Murdoch's face emblazoned across front pages all over the world). So, I am shocked when Wendi announces, suddenly, > matter of factly, as the make-up is swept across her face: "Well, London's shit." But that's the amazing thing about this woman, whose public persona has until now seemed aloof and enigmatic. She's unnervingly straightforward. It's the same straightforwardness I see days later at a parliamentary select committee hearing in London, when she springs across the floor (and delivers a mean blow) in defence of her husband.

Standing at just over 5ft 9in, and with the kind of looks usually reserved for a Bond villainess, 42-year-old Wendi is the 80-year-old media tycoon Rupert Murdoch's third wife. He married her in 1999 on board his yacht The Morning Glory, 17 days after his divorce from Anna, the mother of Lachlan, James and Elisabeth, and after 31 years of marriage. The divorce was reported to have been surprising and deeply hurtful: at the time, Anna, who has since remarried, told Australian Women's Weekly: "Rupert's affair with Wendi Deng - it's not an original plot - was the end of the marriage. I thought we had a wonderful happy marriage. Obviously we didn't." Two children followed soon thereafter, Grace (now nine and a half) and Chloe (now eight), both of whom will inherit, at 30, the same economic interest in their father's trust as his older children. Given that Wendi is believed to be the guardian of her children's interests until they reach that maturity, she is possibly one of the most powerful players in the family's fortune. No wonder the world has speculated ever since as to just who this formidable former employee must be.

I first met Wendi earlier this year at the New York home of actor Hugh Jackman (who makes a cameo appearance in her film) and his wife Deborra-Lee. Wendi had popped in for a quick bite before going on to L'Wren Scott's fashion show. Anticipating a tough, possibly cold and unfriendly sort, I found instead a warm, affectionate woman who bore no trace of froideur. I was also struck by how knowingly fashionable she was: in that season's It-skirt from Prada, black short fitted jumper and knee-high flat black boots. We gossiped about exercise, facials and fashion; though direct in her speech, she was also inarguably charming.

Back then, she was excited about the forthcoming Oscars. I asked her what she was wearing: "Anna is helping me find a dress," she told me briskly, of US Vogue editor Anna Wintour. Wendi, I soon came to understand, always starts at the top. Her conversation was peppered with famous names: her closest friends include Jackman, Nicole Kidman and Tony Blair (all of whom are godparents to the couple's children, all of whom attended the christening garbed in white, as the guests of Queen Rania, on the banks of the river Jordan), and "the Google guys", Larry Page and Sergey Brin. Yet her habit didn't seem snobby or name-dropping - rather as though she simply assumed, because she knew them, so might you. She was excited also about the recent launch of Art.sy, a digital art project she was backing with her friend Dasha Zhukova, and the debut of her first project as a film producer, Snow Flower and the Secret Fan, a glossy movie based on the bestselling pan-historical novel by Lisa See, to whom she was introduced by her former neighbour Amy Tan (of The Joy Luck Club). But that was then.

I worry about him being alone

When we meet again, a few days after the shoot, at the Four Seasons Hotel in New York, she looks tired. "I haven't slept properly for weeks," she sighs, giving me a warm hug before sitting down. (Wendi is very tactile, often touching or holding your arm or hand to make a point in conversation.) She's immaculate, again, in another Prada pencil skirt and a pale blue shirt by J Mary (the same shirt, I realise later, she wore to the select committee hearing) and Lanvin flat sandals. Her hair, as always, is loose.

She's worried about not being in London, for her husband. "Of course, as Rupert's wife, I think it's unfair on him to be going through this," she says of the media storm. "I worry about him being alone. He has no PR people advising him. But he is with his friend who he has worked with for over 50 years - so he has support." I wonder if the friend is Les Hinton, chief executive officer of the Dow Jones and Murdoch's most trusted lieutenant - who will himself resign within hours of our conversation - but Wendi doesn't elaborate. I get a tangible sense of a family under siege, and that this is totally unprecedented. "He tells me not to come," she continues. "But I'm flying to London for the hearing. I want to be with him."

Most of all, Wendi worries about the children. "It's Chloe's eighth birthday and we will miss it [the family had been planning a pool party at their ranch in Carmel]. For us - and the children - that is very hard," she says, before adding, tellingly, "although emotional sadness will help them build character and make them stronger." Are the children aware of what is happening in London? "Oh yes. We don't talk to them like babies. They know all about the phone hacking. But, to be honest, they are children and would rather talk about the camping trip they have just come back from with cowboys." I ask whether Matthew Freud (the PR guru and Murdoch's son-in-law) is advising Rupert. "No, no," she responds quickly. "Too close."

Our children know all about the phone hacking

Despite the maelstrom of events enveloping her husband and the "emotional sadness" of being away from her family, Wendi waves her concerns aside to talk about the film she has made with her partner Florence Sloan - her first with their company, Bigfoot Productions. Set in China, directed by Wayne Wang, and co-starring Hugh Jackman, Lotus Flower explores the nature of friendship between women and sets its action between a small village in China in the nineteenth century and present-day Shanghai. Specifically, it centres on the subject of laotong, the secret language used by women in letters which enabled them to talk about their true feelings, their marriages and their experiences outside the rigid traditions that bound them in the homes.

It is perhaps little wonder that Wendi was moved by the tale of women's endurance. "When I read this book four years ago, I somehow felt there was a connection," she explains. "My grandmother died in childbirth and my great-aunt lived with us. She had bound feet. She never knew how to read or write. And this story is very much at the heart of Lotus Flower."

Born on December 8 1968, Wendi's own childhood was full of its own rigorous discipline. "I grew up in a little funny town called Xuzhou, in the countryside, very poor. We didn't have hot water. We were four children: three girls and a boy." Wendi is the youngest of the daughters and her brother is the youngest child. She adds: "These days, in the countryside, it is still more important to have boys. But not in the city: there they have realised how smart women can be!"

Deng protecting her husband from being hit in the face with a custard pie during the Leveson Inquiry

Deng's parents were engineers, and her two older sisters trained also in the family trade. "My parents pushed us very hard to work, both in the home doing chores and cooking, and at school. They were very > strict. Much stricter than Tiger Mom," she laughs, referring to her friend Amy Chua's bestselling parenting memoir. "When we grew up, you did what your parents told you. Mine wanted me to go to medical school. It was not my choice. It was 1985, and I did what I was told." She stops. "They were thinking practically," she continues. "If I went to medical school, I could look after them when they were old." In many ways she has: her parents now live in the United States, her brothers and sisters move between America and Shanghai.

"I wasn't necessarily the brightest in my family," she continues. "I think my older sister was probably more clever, but I worked very hard." She excelled in her class. "My parents were so tough. In the summer when everyone else was on vacation I had to study the whole textbook for next year so I would be ahead in class." For Wendi, 99 per cent was not an option. "It had to be 120 per cent."

She expects similar of her own children. "Wendi and Rupert are incredibly family orientated," says Hugh Jackman, Grace's godfather. ("She was his translator in China," says Wendi.) "She is quite a strict mother, and it is very important to her that the girls don't take anything for granted. And she wants them to have a spiritual life, which in many ways is surprising - as that was not at all a part of her childhood. They go to church and Sunday school regularly, and when we go over to the house at the weekends she often makes yum cha [dumplings] with the girls for us, the way she was taught to make them as a child."

Then again, he adds, she's "always been very inquisitive about show-business. She's amazing at the details. Often when she and Rupert get talking about that stuff, I am left in the dark, but she loves it. They can talk about it forever."

Wayne Wang also attests to her extraordinary tenacity. When one of their two lead actresses, Zhang Ziyi, pulled out at the last minute, "Wendi hit the phones. For her, 'no' is not an option. She had to find a big-name Chinese actress who could speak English and have an international appeal. These are not easy to find at the best of times, but we had no time. Wendi flew to Hong Kong to meet Bingbing Li and closed the deal. She really gets things done and that is not at all easy in China," he adds. "Wendi used all her contacts, pulling in favours for us everywhere. She was closely involved in everything, especially the modern costumes. Wendi would come on set and say: 'Why is the actress wearing those shoes? She should be wearing Louboutins.' She understood the importance of people recognising those red soles in context of the character, what kind of woman she was."

Wendi's contacts book is extensive. And she's an extremely confident networker, a fact I bear witness to at a screening of the film, in New York, the night before our meeting. She wore a pale blue beaded dress by her friend Peter Dundas, for Pucci; the event was hosted by her friends Kidman, Deborra-Lee Jackman, Diane von Furstenberg and Ivanka Trump; and there was a dinner afterwards at Von Furstenberg's home, catered by Mr Chow. Even within this starry milieu, Wendi exuded a particular charisma. I was reminded of a recent quote by Michael Wolff, author of the famed Murdoch biography The Man Who Owns the News, and one of Murdoch's staunchest critics: "She has instant stature, because she's a Chinese woman who behaves like an American woman. A Chinese woman who isn't the least bit indirect. Every man in the office has a Wendi crush or fixation." Despite being the focus of the event, Wendi didn't stay late. "Gotta get home," she whispered to me at the door. "My feet are killing me."

Nicole Kidman and Wendi have been friends for years. "Wendi is all about friendship between women," she explains from her home in Tennessee. The two women bonded soon after Wendi and Murdoch met. "I think we were both lonely and kind of isolated - Wendi in this big new powerful world, and it was a time in my life where I was very exposed. We just clicked. We understood each other. I sort of had a feeling for the psychology of Wendi. We both came from strict backgrounds. I was brought up in the church and believe that it is important to have a moral compass wherever you find it. Wendi also has found it through church and Sunday school."

I had never even been in a supermarket before coming to America

She hasn't always negotiated the moral compass quite so laudably. While a strict moral upbringing surely propelled Wendi through medical school, her subsequent decision to abandon it halfway through and head to America illustrates determination of quite another kind. "At the time I left medical school I was living in Guangzhou, a big city near Hong Kong, and I started to meet people who had relatives in Hong Kong and America," she says. "And in China, at that time, the idea of getting out and going to America was the stuff of dreams." It was one of these meetings that introduced her to an American family called the Cherrys - Jake, his wife Joyce, and their young children. Joyce taught her English and they soon became close, so much so that when Joyce and the children returned to the USA, Jake suggested they sponsor the teenaged Wendi to study at California State University. Wendi arrived in Los Angeles and moved in with the family. Not long after, Joyce discovered her former pupil was having an affair with her husband. The Cherrys divorced, and Wendi and Jake married. The marriage lasted four months, and Wendi got a Green Card. When I ask Deng to confirm that this story is accurate, she replies only: "Yep."

Maybe if she hadn't ended up being married to one of the most famous men in the world this story would not be of such lurid interest. A young girl who didn't have a fridge or a television in her home until she was 15 must certainly have been quite impressionable. She certainly wasn't afraid of the effort it would require to make a life for herself in America.

"I was willing to do anything," she explains. "I studied and worked in a Chinese restaurant to support myself. People would say to me 'Oh you must be missing home', but I had grown up hard. I was so happy to be there. I had never even been in a supermarket before coming to America. At home, my parents wouldn't let me open the refrigerator, because they worried I'd damage the door by opening it too many times."

I was the first Chinese woman at Star TV - usually the women pushed the tea trolley

Wendi worked extremely hard, and did extremely well, eventually earning her MBA from Yale Business School. And, after a stint at the Murdoch-owned Fox TV in 1996, she won a position at Star TV, Murdoch's Asian satellite service, in Hong Kong. So many stories circulate as to how Deng and her boss met, she sets the record straight. "After I got my MBA I worked as a business development manager with two other MBAs. We went through a very protracted and intensive interview process and they hired me and one other male graduate. And, in 1997, we went to work together at Star. This Jewish boy and me, a Chinese woman. I was the first Chinese woman there to be a manager - usually the women pushed the tea trolley." And Rupert? "In 1998, Rupert was in a meeting and he was asking what was going on in China and they brought me into the meeting and that was how we met." They got married in June 1999.

It's too easy to write Wendi's marriage off as one of ruthless ambition. But, to my mind, the marriage seems much more a meeting of minds - a shared ambition and fascination with the business of making money. "Of course, I realise how extraordinary my life is," she says. "I think I am very defined by how hard I had to work for my education, and I apply that discipline throughout my life. As for what other people think of me, I could worry about that every day, but I choose not to." She is bolstered by her husband's support. "Rupert thinks I have a good head on my shoulders. Whatever I do he is very involved in." Deborra-Lee Jackman agrees. "Rupert loves that Wendi wants to use her brains. It makes him proud to see her achieve her goals."

"She's so not the type to be sitting by a pool," says her friend, Daily Beast and Newsweek editor Tina Brown, who co-hosted a dinner with Wendi and Dasha Zhukova at last year's Art Basel to launch their art site. "She was fabulous to work with, a real pro, terrific at bringing people together and very pro-active. She is really making her own mark for herself, producing across the board. She makes things happen and has fun."

"She's much more relaxed than you would think," agrees Kidman. The two women recently attended a wrap party for one of Kidman's films. "I told her not to bother coming, it was going to be raucous. But she wanted to - and she danced all night!"

Wendi certainly doesn't let her position stop her from trying to keep the normal things important in her life. Her girls are encouraged to work hard. "Rupert did such a good job with his big children," she says. "I really make sure that my girls understand the importance of education. I don't want them to be spoilt and only know private-school kids. I want them to behave well by example. I believe if you are nice to people, children will follow. Likewise, if you are rude to people, children will follow." She's also well aware of just how privileged she is. But she seems to have found her own identity as a working mother, wife and friend. She and Sloan are keen to develop more movies that would work both in China and internationally, and there is much talk, currently, of her trying to secure the rights to Amy Chua's Battle Hymn of the Tiger Mother. But lest anyone forgets, the family comes first. As Hugh Jackman observes: "If there was one thing that would stop her from being a producer, it would be her children."

Right now, she is thinking about her forthcoming trip to London. "There are so many photographers outside our house," she says, absent-mindedly, "what do you think I should wear?" I suggest a pair of jeans and her T-shirt with the film's name on the front. "Yes," she laughs. "Good idea." How will the family spend their summer? "Usually, we are on the boats and we meet up with Rupert's kids on their boats." Rather like the soap opera Dallas, I imagine a floating Southfork, with Rupert as JR, all the other Ewings bobbing around him and, if the rumours are to be believed, family dynamics that would rival even its most fabulous storylines. "But all this we don't know," she finishes. "We have to see what happens in London."

Four days later I watch Wendi Deng sitting behind her husband in front of the parliamentary select committee, a situation she must never have imagined. Dressed, I am sure, with as much attention to detail as she gave to her actresses on the film: not too fashion, not too showy, almost no jewellery, yet her jacket - that pink - is the only colour in the room. I observe her leaning forward, implacable, focusing intently on every word said. I see her concern for her husband, her hand reaching out to support him and signalling to him gently when he bangs too hard on the table in front of the microphones. I find myself moved by her obvious concern for him.

Then, as the drama unfolds, Rupert is attacked - by, it emerges, a man with a foam pie. I see Wendi leap forward and challenge his assailant; all instinct, all power. I send her a text congratulating her. Moments later I get a reply: "XOXOXOX". If Rupert Murdoch is looking for someone to help re-brand the image of his company, he need look no further than his wife.